阅读说明：本技术 一种钛合金t型截面环件的局部模锻及轧制联合成型方法 (Local die forging and rolling combined forming method for titanium alloy T-shaped section ring piece ) 是由 王世超 霍达 黄坤 于杰 丁学生 闫伟宁 张兰涛 宋冬行 张柯 冯谊勋 于 2020-04-09 设计创作，主要内容包括：本发明公开了一种钛合金T型截面环件的局部模锻及轧制联合成型方法,为获得具备复杂截面形状,尺寸精密,性能优异的钛合金T型截面环件,其技术方案为：将锯切好的合金棒材加热至始锻温度并保温,经镦粗、冲孔两道工序制备近矩形环坯；采用局部开式模锻,对近矩形环坯靠近外圆部位的上下两端面施加压力,通过局部变形得到异形预制环坯；将异形预制环坯加热至钛合金的始锻温度并保温,随后放入轧环机中,利用主辊碾轧模具以相应转速结合芯辊径向进给速度对异形预制环坯进行轧环,得到T型截面环件。本发明的一种钛合金T型截面环件的局部模锻及轧制联合成型方法不仅能最大限度的简化生产流程,降低零件的生产成本,保证环件尺寸,而且该方法保留了的完整的锻件流线,确保环件具备良好的力学性能。(The invention discloses a local die forging and rolling combined forming method of a titanium alloy T-shaped cross section ring piece, which aims to obtain the titanium alloy T-shaped cross section ring piece with complex cross section shape, precise size and excellent performance, and adopts the technical scheme that: heating the sawed alloy bar to the initial forging temperature, preserving heat, and preparing a nearly rectangular ring blank through two working procedures of upsetting and punching; local open die forging is adopted, pressure is applied to the upper end face and the lower end face of the part, close to the excircle, of the approximately rectangular ring blank, and the special-shaped prefabricated ring blank is obtained through local deformation; and heating the special-shaped prefabricated ring blank to the initial forging temperature of the titanium alloy, preserving heat, then putting the special-shaped prefabricated ring blank into a ring rolling machine, and rolling the special-shaped prefabricated ring blank by using a main roller rolling die at a corresponding rotating speed in combination with the radial feeding speed of a core roller to obtain the T-shaped section ring piece. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece, disclosed by the invention, not only can simplify the production flow to the maximum extent, reduce the production cost of parts and ensure the size of the ring piece, but also can reserve a complete forging streamline and ensure that the ring piece has good mechanical properties.)

1. A local die forging and rolling combined forming method for a titanium alloy T-shaped section ring piece is characterized by comprising the following steps:

placing the approximately rectangular ring blank in a die for local die forging to prepare a special-shaped prefabricated ring blank;

heating the special-shaped prefabricated ring blank to a temperature range of 40-20 ℃ below the beta transition temperature, namely (T beta-40) DEG C- (T beta-20) DEG C, and preserving heat, wherein the shortest heat preservation time is not less than (0.6-1.1) min/mm multiplied by the effective section thickness of the special-shaped ring blank; and (4) performing ring rolling after the heat preservation is finished, and finally obtaining the titanium alloy ring piece.

2. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece according to claim 1, wherein the preparation process of the approximately rectangular ring blank comprises the following steps: sawing the alloy bar according to a preset specification, heating the sawed alloy bar to a temperature range of 40-20 ℃ below the beta transition temperature, namely (Tbeta-40) DEG C-Tbeta-20℃, and preserving heat, wherein the shortest heat preservation time is not less than (0.6-1.1) min/mm multiplied by the diameter of the alloy bar; then upsetting and punching are carried out to manufacture a nearly rectangular ring blank.

3. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece according to claim 1, wherein open die forging is adopted in the die forging process, pressure is only applied to the upper end face and the lower end face of the approximately rectangular ring blank close to the excircle portion, and local deformation is carried out to obtain the special-shaped prefabricated ring blank.

4. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece according to claim 3, wherein an included angle between two inclined planes at an outer circle part of the special-shaped prefabricated ring blank is 45-60 degrees.

5. The method for local die forging and rolling combined forming of the titanium alloy T-shaped section ring piece according to claim 3, wherein the maximum die forging pressure F is about 1 x 10⁷N～1.7×10⁷N, the calculation mode is as follows: f =2 μ σ S, wherein μ is the friction coefficient of the ring material and the die, σ is the deformation resistance of the ring material at the finish forging temperature, and S is the projected area of the contact surface of the ring blank and the die.

6. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece according to claim 1, wherein in the ring rolling process, the optional rotation linear speed range of a main roller is 0.4-1.6 m/s, and the radial feeding speed of a core roller is divided into three stages: in the initial stage of ring rolling, the ring rolling stabilization stage and the ring rolling circle calibration and shaping stage, the radial feeding speed range of the core roller is 0-3 mm/s.

7. The combination of the local die forging and the rolling of the titanium alloy T-section ring piece according to claim 6The forming method is characterized in that the maximum ring rolling force is 7 multiplied by 10 in the ring rolling process⁵N～1.5×10⁶N, calculated as P =2kbL (1+ h)₀/4L+m3L/8 h₀+ m3L/4b), where k is the ring material shear yield strength, b is the ring height, L is the contact arc length, h₀Radial wall thickness, m is the friction factor.

8. The local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece according to claim 1, wherein the rolling ratio lambda of the T-shaped section special-shaped ring piece is 1-2.

9. The combined local die forging and rolling forming method for the titanium alloy T-shaped section ring piece according to any one of claims 1 to 8, wherein the T-shaped section ring piece is made of an alpha type titanium alloy and an (alpha + beta) type titanium alloy.

Technical Field

The invention belongs to the technical field of forging, and particularly relates to a local die forging and rolling combined forming method for a titanium alloy T-shaped section ring piece.

Background

The titanium alloy belongs to a high-specific strength material, and a ring piece with a T-shaped section of the titanium alloy is often used as a key part in engines and gas turbine equipment and is widely applied to the fields of aerospace, ships and the like. Because the ring piece with the T-shaped section of the titanium alloy is always troubled by the problems of high forging processing difficulty, low size precision of forged parts and the like, the production and manufacturing efficiency is low. Therefore, the technology for forming the ring with the T-shaped section of the titanium alloy is simple and convenient in process, and easy for mass and rapid production is provided. At present, the domestic main forming method of the ring piece with the T-shaped section comprises the following steps: integral open die forging or closed die forging forming, free forging of a nearly rectangular ring blank, direct multiple ring rolling forming, rolling of the rectangular ring blank and large-allowance machining forming. These methods are often influenced by factors such as the production cost of parts, comprehensive mechanical properties and dimensional requirements, and the expected ideal effect is difficult to achieve.

The integral open die forging or closed die forging is adopted for forming, the size precision of parts is higher, but the deformation resistance of materials in a pre-forging die impression and a finish forging die impression in the forming process is large, the required tonnage of equipment is large, the die impressions are easy to lose effectiveness due to abrasion or cracking, the service life is short, and the production cost is high. The trimming process after the integral open die forging can damage the integrity of a metal streamline of the forge piece, thereby influencing the mechanical property of the forge piece.

The method adopts freely forged nearly rectangular ring blanks and then directly carries out ring rolling forming for multiple times, the process is simple, but the number of ring rolling fire times becomes a 'double-edged sword' which restricts the dimensional precision and the mechanical property of parts, the ring rolling fire times are few, the special-shaped part of the outer diameter of the ring piece is difficult to completely fill a rolling die, and the dimensional requirement of a final product cannot be ensured; the ring is hot, which can easily cause the defects of coarse crystal grain, damage and crack of the forging, and increase the economic cost.

The process is simple, but the material utilization rate is low and the economic benefit is low. In addition, the machining seriously damages the integrity of the metal streamline of the forging and reduces the mechanical property of the part.

The Chinese patent with publication number CN101279345A discloses a rolling forming method of a titanium alloy deformed ring forging, which comprises the working procedures of blanking, upsetting, punching and rolling, wherein the method comprises the steps of performing primary rolling on a punched round cake-shaped forging twice with deformation of 30-35% to obtain a rectangular prefabricated ring blank, and then combining a rolling die to perform rolling forming for the third time through a ring rolling machine. The ring rolling process has the problems of multiple rolling fire, long production period and incomplete rolling mold filling in the process of converting the rectangular prefabricated ring blank into the special-shaped ring.

For another example, chinese patent publication No. CN106984747 discloses a method for designing a TC4 alloy blank for a T-section ring with a special shape, which calculates the final size of the blank according to the characteristics of metal flow during ring rolling and the principle that the volume is not changed during the plastic deformation of titanium alloy ring rolling. The method only explains the control of the size of the blank of the T-shaped section special-shaped ring piece from the theoretical calculation angle, does not disclose the specific process steps for rolling the T-shaped section special-shaped titanium alloy ring forging, and does not solve the problem of insufficient metal filling in the cerclage process from the aspect of actual production and manufacturing.

Therefore, the invention discloses a local die forging and rolling combined forming method of the titanium alloy T-shaped section ring piece.

Disclosure of Invention

The invention aims to provide a local die forging and rolling combined forming method for a titanium alloy T-shaped section ring piece. The method not only saves the process investment and the raw material consumption, does not need to rely on a die cavity with short service life and high cost, but also can ensure the streamline integrity of the forge piece to the maximum extent and ensure the mechanical property of the final product.

In order to achieve the purpose, the local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece adopts the following technical scheme that the method comprises the steps of preparing a nearly rectangular ring blank, preparing a special-shaped prefabricated ring blank and rolling a ring.

Further, the preparation of the near-rectangular ring blank comprises the following steps: sawing, heating, upsetting and punching.

The sawing step comprises the following steps: and sawing the alloy bar according to the preset specification.

The heating step is as follows: heating the sawed alloy bar to a temperature range of 40-20 ℃ below the beta transition temperature, namely (Tbeta-40) DEG C-Tbeta-20℃, and preserving heat, wherein the shortest heat preservation time is not less than (0.6-1.1) min/mm multiplied by the diameter of the alloy bar;

the upsetting step comprises the following steps: using a press machine, and upsetting the whole body to H = 95-120 mm after eliminating sharp corners by riveting and upsetting;

furthermore, in order to avoid the temperature rise of the material caused by excessive deformation, the deformation during upsetting is controlled to be 30-50%.

The punching step comprises the following steps: punching phi 115-phi 145mm by using a punch, wherein the thickness of a punching bottom sheet is less than or equal to 45mm, and preparing the nearly rectangular ring piece.

Further, the production of the profiled ring preform comprises: and local die forging.

The local die forging step is as follows: open die forging is adopted on a press, a nearly rectangular ring blank is placed into a preheated die, pressure is only applied to the upper end surface and the lower end surface of the nearly rectangular ring blank close to the excircle, and local deformation is carried out to prepare a special-shaped prefabricated ring blank;

further, the included angle of the two inclined planes at the excircle part of the special-shaped prefabricated ring blank is 45-60 degrees;

further, the maximum die forging pressure F is about 1X 10⁷N～1.7×10⁷N；

Further, the maximum die forging pressure is calculated in the following manner: f =2 μ σ S, wherein μ is the friction coefficient of the ring material and the die, σ is the deformation resistance of the ring material at the finish forging temperature, and S is the projected area of the contact surface of the ring blank and the die.

Further, the rolling ring comprises: heating and rolling.

The heating step is as follows: and heating the special-shaped prefabricated ring blank to a temperature range of 40-20 ℃ below the beta transition temperature, namely (T beta-40) DEG C to (T beta-20) DEG C, and preserving heat, wherein the shortest heat preservation time is not less than (0.6-1.1) min/mm multiplied by the effective section thickness of the special-shaped prefabricated ring blank.

The rolling step comprises the following steps: placing the heated special-shaped prefabricated ring blank on a ring rolling machine, enabling an external convex part of the special-shaped prefabricated ring blank to correspond to an internal concave part of a main roller mold, enabling the main roller mold to move at an axial autorotation linear speed, and rolling the special-shaped prefabricated ring blank to a required size and shape by a core roller at a certain radial feeding speed;

further, the optional axial rotation speed range of the main roller is 0.4-1.6 m/s, and the radial feeding speed of the core roller is divided into three stages: in the ring rolling initial stage, in the ring rolling stabilization stage and the ring rolling circle calibration stage, the radial feeding speed ranges from 0 mm/s to 3 mm/s;

further, in the initial ring rolling stage, the core roller feeds the special-shaped prefabricated ring blank into a ring rolling die through radial feed motion, so that the blank is ensured to be in contact with the die and the ring rolling is started; in the ring rolling stabilization stage, the axial autorotation motion of the main roller is combined with the radial feed motion of the core roller, so that the special-shaped prefabricated ring blank is ensured to be continuously and stably filled in a ring rolling die; in the ring rolling and rounding stage, the core roller does not perform radial feeding motion, only the main roller performs axial rotation motion, and the ring piece is rounded and rounded, so that the size precision of the final ring piece is ensured;

furthermore, in the ring rolling process, the maximum ring rolling force is 7 multiplied by 10⁵N～1.5×10⁶N；

Further, the maximum ring rolling force was calculated in a manner of P =2kbL (1+ h)₀/4L+m3L/8 h₀+ m3L/4b), where k is the ring material shear yield strength, b is the ring height, L is the contact arc length, h₀Radial wall thickness, m is the friction factor;

further, the actual forming deformation is the rolling ratio lambda of the sectional area of the intermediate blank of the ring blank after the open die forging local deformation to the sectional area of the final ring piece.

The invention discloses a local die forging and rolling combined forming method of a titanium alloy ring piece, which adopts the technical scheme of saw cutting, heating, upsetting, punching, die forging and ring rolling.

Compared with the prior art, the invention has the following advantages: large allowance machining is not needed, no trimming step is needed, the material utilization rate is improved to the maximum extent, and the integrity of a forging flow line is reserved; the special-shaped prefabricated ring blank prepared by local die forging is completely filled in a ring rolling die without multiple ring rolling; the process is simple, complex forging impression and large-tonnage complex forming equipment are not needed, the cost of the forge piece is saved, and the technology is suitable for various enterprises.

Drawings

The invention is further described with reference to the following figures and specific embodiments.

FIG. 1 is a schematic view of partial swaging in the present invention; wherein: 1. an upper die; 2. a nearly rectangular ring blank; 3. and (5) a lower die.

Fig. 2 is a schematic view of a partially swaged profiled preform in accordance with the present invention.

Fig. 3 is a schematic view of a main roll rolling mold according to the present invention.

FIG. 4 is a schematic view of the shaped preform ring shown in FIG. 2, finally rolled in the rolling mold of FIG. 4 to form a mold. Wherein: 6. an upper shoulder; 7. a lower shoulder; 8. an upper inclined plane of the special-shaped prefabricated ring blank; 9. a lower inclined plane of the special-shaped prefabricated ring blank; 10. a V-shaped groove is arranged; 11. a V-shaped groove is arranged; 12. an internal U-shaped groove.

Fig. 5 is a schematic view of the final special-shaped ring piece after the ring rolling forming of the invention.

Detailed Description

Example 1

In this example, the specific implementation of the method is described in detail by taking alloy with the designation TC4 as an example:

the main chemical element contents of the TC4 alloy are as follows:

TABLE 1 main chemical elements of TC4 alloy

Element(s)

Al

V

Ti

Fe

C

N

H

O

Content (%)

5.5～6.8

3.5～4.5

Balance of

≤0.30

≤0.10

≤0.05

≤0.015

≤0.20

The method for implementing the local die forging and rolling combined forming of the titanium alloy ring piece needs to provide a band sawing machine, a forging heating furnace, a press machine, a ring rolling machine and a manipulator.

The invention discloses a local die forging and rolling combined forming method of a titanium alloy T-shaped section ring piece, which adopts the following technical scheme that the method comprises the following steps: preparing a nearly rectangular ring blank, preparing a special-shaped prefabricated ring blank, and rolling a ring.

Further, the preparation of the near-rectangular ring blank comprises the following steps: sawing, heating, upsetting and punching.

The sawing step comprises the following steps: and sawing the TC4 alloy bar according to the preset specification.

The heating step is as follows: and heating the sawed TC4 alloy bar to 960 ℃, and preserving heat, wherein the shortest heat preservation time =0.7min/mm multiplied by the TC4 alloy bar diameter is 180 mm.

The upsetting step comprises the following steps: using a press machine, and upsetting the whole body to H =96 +/-5 mm after eliminating sharp corners by riveting and upsetting;

furthermore, in order to avoid the temperature increase of TC4 caused by excessive deformation, the deformation during upsetting is controlled to be 30-35%.

The punching step comprises the following steps: and punching phi 125 +/-5 mm by using a punch, and punching the bottom plate to be 35mm in thickness to prepare the TC4 approximately rectangular ring piece 2.

Further, the preparation of the special-shaped prefabricated ring blank comprises the following steps: and local die forging.

The local die forging step is as follows: as shown in fig. 1, open die forging is adopted on a press, a nearly rectangular ring blank 2 is placed between a preheated upper die 1 and a preheated lower die 3, pressure is only applied to the upper end surface and the lower end surface of the nearly rectangular ring blank 2 close to the excircle part, and partial deformation is carried out to prepare a TC4 special-shaped prefabricated ring blank 4;

further, the included angle alpha of two inclined planes at the excircle part of the TC4 special-shaped precast ring blank 4 is 48 degrees;

further, the maximum die forging pressure F is about 1.06X 10⁷N；

Further, the maximum die forging pressure is calculated in the following manner: f =2 μ σ S, wherein μ is the friction coefficient of the TC4 alloy ring material and the die, μ =0.3, σ is the deformation resistance of TC4 at the finish forging temperature of 800 ℃, σ =323MPa, S is the projection area of the contact surface of the ring blank 2 and the die 1, and S =545.2cm²。

The local open die forging has the following process characteristics: the forging flow lines generated in the special-shaped prefabricated ring blank are distributed along the contour of the forging piece along the shape, so that the comprehensive mechanical property of the ring blank is favorably improved; the special-shaped prefabricated ring blank has no burrs, trimming is not needed in later processing, and the material utilization rate is high; only local deformation of the nearly rectangular ring blank is realized, the die is simple, the tonnage of required equipment is small, and the production cost is low.

The local open die forging can obviously reduce the material deformation resistance in the forging process, reduce the dependence on large-tonnage die forging equipment, quickly obtain the special-shaped prefabricated ring blank which can ensure the size and quality requirements of the final rolled ring, and has low production cost and high production efficiency. The local open die forging does not damage the integrity of a forging streamline, so that the ring rolling forming quality and the batch stability of the ring piece are high.

Further, the rolling ring comprises: heating and rolling.

The heating step is as follows: heating the special-shaped prefabricated ring blank 4 to the initial forging temperature of 960 ℃, and preserving heat, wherein the shortest heat preservation time =1.0min/mm multiplied by the effective section thickness of the special-shaped prefabricated ring blank of 85 mm;

the rolling step comprises the following steps: placing the heated special-shaped prefabricated ring blank 4 on a ring rolling machine, enabling an external convex part of the special-shaped prefabricated ring blank 4 to correspond to an internal concave part of a main roller mold 5, and rolling the special-shaped prefabricated ring blank 4 to the required shape and size by combining the axial rotation linear speed of the main roller mold 5 with the axial rotation linear speed of 1.3m/s and the radial feeding speed of a core roller with the radial feeding speed of 1.2 mm/s;

further, in the ring rolling process, the process of gradually filling the main roll mold of the ring rolling machine with metal through plastic deformation is shown in fig. 4. In the initial stage of ring rolling, as shown in fig. 4a, the core roller feeds the special-shaped prefabricated ring blank 4 into the rolling main roller die 5 by radial feed motion, the blank contacts with the die and starts to roll the ring, and the upper shoulder 6 and the lower shoulder 7 of the main roller die 5 respectively extrude the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped prefabricated ring blank 4. According to the principle that the volume of metal is not changed in plastic deformation and the law of minimum resistance, along with the gradual increase of the diameter of the ring blank, the metal at the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped ring blank 4 flows to the axial and radial vacant areas in the main roller mold 5; in the ring rolling stabilization stage, as shown in fig. 4b and 4c, the radial feed motion of the core roller is combined with the axial rotation motion of the main roller, and the special-shaped prefabricated ring blank 4 firstly completes the filling of an upper V-shaped groove 10 and a lower V-shaped groove 11 outside an upper shoulder 6 and a lower shoulder 7 in the main roller mold 5 and then completes the filling of a U-shaped groove 12 inside the upper shoulder 6 and the lower shoulder 7 in the main roller mold 5; in the ring rolling and rounding stage, as shown in fig. 4d, the core roller does not perform radial feed motion, only the main roller performs axial rotation motion, and the ring is rounded and rounded, so that the shield machine cutter ring special-shaped ring as shown in fig. 5 is finally obtained;

furthermore, in the ring rolling process, the maximum ring rolling force is 7.95 multiplied by 10⁵N；

Further, the maximum ring rolling force was calculated in a manner of P =2kbL (1+ h)₀/4L+m3L/8 h₀+ m3L/4b), where k is the ring material shear yield strength, k =186.48MPa, b is the ring height, b =92mm, L is the contact arc length, L =1.75mm, h₀Is radial wall thickness, h₀=85mm, m is the friction factor, m = 0.7;

further, the actual forming deformation is the rolling ratio lambda of the sectional area of the intermediate blank of the ring blank after the open die forging local deformation to the sectional area of the final ring piece. In this embodiment, the sectional area of the intermediate blank of the ring blank after the local die forging deformation is 7358mm²The sectional area of the final ring piece is 4964 mm²And λ is 1.48.

The invention relates to a titanium alloy local die forging and rolling combined forming method, which adopts the technical scheme of saw cutting, heating, upsetting, punching, die forging and ring rolling.

Compared with the prior art, the invention has the following advantages: large allowance machining is not needed, no trimming step is needed, the material utilization rate is improved to the maximum extent, and the integrity of a forging flow line is reserved; multiple ring rolling is not needed, and the special-shaped prefabricated ring blank prepared by local die forging can be completely filled in a ring rolling die; the process is simple, complex forging impression and large-tonnage complex forming equipment are not needed, the cost of the forge piece is saved, and the technology is suitable for various enterprises.

Therefore, the local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece can effectively simplify the process flow, and the titanium alloy ring piece with excellent mechanical property can be manufactured by using a low-cost process method and low-cost equipment.

Example 2

In this example, the specific implementation of the method is described in detail by taking alloy TA15 as an example:

the main chemical element contents of the TA15 alloy are as follows:

TABLE 2 main chemical elements of TA15 alloy

Element(s)

Al

V

Ti

Fe

C

N

H

O

Content (%)

5.5～7.0

0.8～2.5

Balance of

0.25

≤0.10

≤0.05

≤0.015

≤0.15

Element(s)

Zr

Si

Content (%)

1.5～2.5

0.15

The method for implementing the local die forging and rolling combined forming of the titanium alloy ring piece needs to provide a band sawing machine, a forging heating furnace, a press machine, a ring rolling machine and a manipulator.

The invention discloses a local die forging and rolling combined forming method of a titanium alloy T-shaped section ring piece.

Further, the preparation of the near-rectangular ring blank comprises the following steps: sawing, heating, upsetting and punching.

The sawing step comprises the following steps: and sawing the TA15 alloy bar according to the preset specification.

The heating step is as follows: and heating the sawed TA15 alloy bar to 970 ℃, and preserving heat, wherein the shortest heat preservation time =0.7min/mm multiplied by the TA15 alloy bar diameter 175 mm.

The upsetting step comprises the following steps: using a press machine, and upsetting the whole body to H =100 +/-5 mm after eliminating sharp corners by riveting and upsetting;

furthermore, in order to avoid the temperature rise of TA15 caused by excessive deformation, the deformation amount during upsetting is controlled to be 40-45%.

The punching step comprises the following steps: a punch is used for punching phi 130 +/-5 mm, the thickness of a punching bottom sheet is 35mm, and TA15 near rectangular ring pieces 2 are prepared.

Further, the preparation of the special-shaped prefabricated ring blank comprises the following steps: and local die forging.

The local die forging step is as follows: as shown in fig. 1, open die forging is adopted on a press, a nearly rectangular ring blank 2 is placed between a preheated upper die 1 and a preheated lower die 3, pressure is only applied to the upper end surface and the lower end surface of the nearly rectangular ring blank 2 close to the excircle part, and partial deformation is carried out to prepare a TA15 special-shaped prefabricated ring blank 4;

further, the included angle alpha of the two inclined planes at the excircle part of the TA15 special-shaped prefabricated ring blank 4 is 54 degrees;

further, the maximum die forging pressure F is about 1.07X 10⁷N；

Further, the maximum die forging pressure is calculated in the following manner: f =2 μ σ S, where μ is the friction coefficient of the TA15 ring material with the die, μ =0.28, σ is the deformation resistance of TA15 at the finish forging temperature of 850 ℃, σ =341MPa, S is the projected area of the contact surface of the ring blank 2 with the die 1, and S =520.3cm²。

The local open die forging has the following process characteristics: the forging flow lines generated in the special-shaped prefabricated ring blank are distributed along the contour of the forging piece along the shape, so that the comprehensive mechanical property of the ring blank is favorably improved; the special-shaped prefabricated ring blank has no burrs, trimming is not needed in later processing, and the material utilization rate is high; only local deformation of the nearly rectangular ring blank is realized, the die is simple, the tonnage of required equipment is small, and the production cost is low.

The local open die forging can obviously reduce the material deformation resistance in the forging process, reduce the dependence on large-tonnage die forging equipment, quickly obtain the special-shaped prefabricated ring blank which can ensure the size and the quality of a final rolled ring, and has low production cost and high production efficiency. The local open die forging does not damage the integrity of a forging streamline, so that the ring rolling forming quality and the batch stability of the ring piece are high.

Further, the rolling ring comprises: heating and rolling.

The heating step is as follows: and heating the special-shaped prefabricated ring blank 4 to the initial forging temperature of 970 ℃ and preserving heat, wherein the shortest heat preservation time =1.0min/mm multiplied by TA15 and the effective section thickness of the special-shaped prefabricated ring blank is 92 mm.

The ring rolling step comprises: placing the heated special-shaped prefabricated ring blank 4 on a ring rolling machine, enabling an external convex part of the special-shaped prefabricated ring blank 4 to correspond to an internal concave part of a main roller mold 5, and rolling the special-shaped prefabricated ring blank 4 to the required shape and size by the main roller mold 5 at the axial rotation linear speed of 0.9m/s in combination with the radial feeding speed of 0.8 mm/s;

further, in the ring rolling process, the process of gradually filling the main roll mold of the ring rolling machine with metal through plastic deformation is shown in fig. 4. In the initial stage of ring rolling, as shown in fig. 4a, the core roller feeds the special-shaped prefabricated ring blank 4 into the rolling main roller die 5 by radial feed motion, the blank contacts with the die and starts to roll the ring, and the upper shoulder 6 and the lower shoulder 7 of the main roller die 5 respectively extrude the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped prefabricated ring blank 4. According to the principle that the volume of metal is not changed in plastic deformation and the law of minimum resistance, along with the gradual increase of the diameter of the ring blank, the metal at the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped prefabricated ring blank 4 flows to the axial and radial vacant areas in the main roller mold 5; in the ring rolling stabilization stage, as shown in fig. 4b and 4c, the radial feed motion of the core roller is combined with the axial rotation motion of the main roller, and the special-shaped prefabricated ring blank 4 firstly completes the filling of an upper V-shaped groove 10 and a lower V-shaped groove 11 outside an upper shoulder 6 and a lower shoulder 7 in the main roller mold 5 and then completes the filling of a U-shaped groove 12 inside the upper shoulder 6 and the lower shoulder 7 in the main roller mold 5; in the ring rolling and rounding stage, as shown in fig. 4d, the core roller does not perform radial feed motion, the main roller only performs axial rotation motion, and the ring is rounded and rounded, so that the shield machine cutter ring special-shaped ring as shown in fig. 5 is finally obtained;

furthermore, in the ring rolling process, the maximum ring rolling force is 9.5 multiplied by 10⁵N；

Further, the maximum ring rolling force was calculated in a manner of P =2kbL (1+ h)₀/4L+m3L/8 h₀+ m3L/4b), where k is the ring material shear yield strength, k =196.88MPa, b is the ring height, b =90mm, L is the contact arc length, L =1.77mm, h₀Is radial wall thickness, h₀=100mm, m is the friction factor, m = 0.7;

further, the actual forming deformation is the rolling ratio lambda of the sectional area of the intermediate blank of the ring blank after the open die forging local deformation to the sectional area of the final ring piece. In the embodiment, the sectional area of the intermediate blank of the ring blank after local die forging deformation is 9055mm²The sectional area of the final ring piece is 5831mm²And λ is 1.55.

The invention relates to a titanium alloy local die forging and rolling combined forming method, which adopts the technical scheme of saw cutting, heating, upsetting, punching, die forging and ring rolling.

Compared with the prior art, the invention has the following advantages: large allowance machining is not needed, no trimming step is needed, the material utilization rate is improved to the maximum extent, and the integrity of a forging flow line is reserved; multiple ring rolling is not needed, and the special-shaped prefabricated ring blank prepared by local die forging can be completely filled in a ring rolling die; the process is simple, complex forging impression and large-tonnage complex forming equipment are not needed, the cost of the forge piece is saved, and the technology is suitable for various enterprises.

Therefore, the local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece can effectively simplify the process flow, and the titanium alloy ring piece with excellent mechanical property can be manufactured by using a low-cost process method and low-cost equipment.

Example 3

In this example, the specific implementation of the method is described in detail by taking alloy with the designation TC11 as an example:

the main chemical element contents of the TC11 alloy are as follows:

TABLE 3 main chemical elements of TC11 alloy

Element(s)

Al

Mo

Ti

Fe

C

N

H

O

Content (%)

5.8～7.0

2.8～3.8

Balance of

≤0.25

≤0.10

≤0.05

≤0.012

≤0.15

Element(s)

Zr

Si

Content (%)

0.8～2.0

0.2～0.35

The method for implementing the local die forging and rolling combined forming of the titanium alloy ring piece needs to provide a band sawing machine, a forging heating furnace, a press machine, a ring rolling machine and a manipulator.

The invention discloses a local die forging and rolling combined forming method of a titanium alloy T-shaped cross-section ring piece.

Further, the preparation of the near-rectangular ring blank comprises the following steps: sawing, heating, upsetting and punching.

The sawing step comprises the following steps: and sawing the TC11 alloy bar according to the preset specification.

The heating step is as follows: and heating the sawed TC11 alloy bar to 980 ℃ and preserving heat, wherein the shortest preserving time =0.6min/mm multiplied by TC11 alloy bar diameter 200 mm.

The upsetting step comprises the following steps: using a press machine, and upsetting the whole body to H =115 +/-3 mm after eliminating sharp corners by riveting and upsetting;

furthermore, in order to avoid the temperature rise of the TC11 alloy caused by excessive deformation, the deformation amount during upsetting is controlled to be 35-40%.

The punching step comprises the following steps: punching with a punch with the diameter of 135 +/-5 mm and the thickness of a punching bottom sheet of 40mm to prepare the TC11 near-rectangular ring piece 2.

Further, the preparation of the special-shaped prefabricated ring blank comprises the following steps: and local die forging.

The local die forging step is as follows: as shown in fig. 1, open die forging is adopted on a press, a rectangular ring blank 2 is placed between a preheated upper die 1 and a preheated lower die 3, pressure is only applied to the upper end surface and the lower end surface of the rectangular ring blank 2 close to the excircle part, and partial deformation is carried out to prepare a TC11 alloy special-shaped prefabricated ring blank 4;

further, the included angle alpha of the two inclined planes at the excircle part of the TC11 alloy special-shaped precast ring blank 4 is 57 degrees;

further, the maximum die forging pressure F is about 1.5X 10⁷N；

Further, the maximum die forging pressure is calculated in the following manner: f =2 μ σ S, wherein μ is the friction coefficient of the TC11 alloy ring material and the die, μ =0.3, σ is the deformation resistance of the TC11 alloy at the finish forging temperature of 850 ℃, σ =392MPa, S is the projection area of the contact surface of the ring blank 2 and the die 1, and S =635.1cm²。

The local open die forging has the following process characteristics: the forging flow lines generated in the special-shaped prefabricated ring blank are distributed along the contour of the forging piece along the shape, so that the comprehensive mechanical property of the ring blank is favorably improved; the special-shaped prefabricated ring blank has no burrs, trimming is not needed in later processing, and the material utilization rate is high; only local deformation is carried out on the rectangular ring blank, the die is simple, the tonnage of required equipment is small, and the production cost is low.

The local open die forging can obviously reduce the material deformation resistance in the forging process, reduce the dependence on large-tonnage die forging equipment, quickly obtain the special-shaped prefabricated ring blank which can ensure the size and quality requirements of the final rolled ring, and has low production cost and high production efficiency. The local open die forging does not damage the integrity of a forging streamline, so that the ring rolling forming quality and the batch stability of the ring piece are high.

Further, the rolling ring comprises: heating and rolling.

The heating step is as follows: and heating the special-shaped prefabricated ring blank 4 to the initial forging temperature of 980 ℃ and preserving heat, wherein the shortest heat preservation time =0.6min/mm multiplied by the effective section thickness of the special-shaped prefabricated ring blank of 105 mm.

The rolling step comprises the following steps: placing the heated special-shaped prefabricated ring blank 4 on a ring rolling machine, enabling an external convex part of the special-shaped prefabricated ring blank 4 to correspond to an internal concave part of a main roller mold 5, and rolling the special-shaped prefabricated ring blank 4 to the required shape and size by the main roller mold 5 at the axial rotation linear speed of 1.1m/s in combination with the radial feeding speed of 1.0 mm/s;

further, in the ring rolling process, the process of gradually filling the main roll mold of the ring rolling machine with metal through plastic deformation is shown in fig. 4. In the initial stage of ring rolling, as shown in fig. 4a, the core roller feeds the special-shaped prefabricated ring blank 4 into the rolling main roller die 5 by radial feed motion, the blank contacts with the die and starts to roll the ring, and the upper shoulder 6 and the lower shoulder 7 of the main roller die 5 respectively extrude the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped prefabricated ring blank 4. According to the principle that the volume of metal is not changed in plastic deformation and the law of minimum resistance, along with the gradual increase of the diameter of the ring blank, the metal at the upper inclined surface 8 and the lower inclined surface 9 of the special-shaped prefabricated ring blank 4 flows to the axial and radial vacant areas in the main roller mold 5; in the ring rolling stabilization stage, as shown in fig. 4b and 4c, the radial feed motion of the core roller is combined with the axial rotation motion of the main roller, and the special-shaped prefabricated ring blank 4 firstly completes the filling of an upper V-shaped groove 10 and a lower V-shaped groove 11 outside an upper shoulder 6 and a lower shoulder 7 in the main roller mold 5 and then completes the filling of a U-shaped groove 12 inside the upper shoulder 6 and the lower shoulder 7 in the main roller mold 5; the rolling ring rounding stage is as shown in fig. 4d, the main roller does not perform radial feed motion, only performs axial rotation motion, and performs rounding on the ring piece, and finally, the shield machine cutter ring special-shaped ring piece as shown in fig. 5 is obtained;

furthermore, in the ring rolling process, the maximum ring rolling force is 1.15 multiplied by 10⁶N；

Further, the maximum ring rolling force was calculated in a manner of P =2kbL (1+ h)₀/4L+m3L/8 h₀+ m3L/4b), where k is the ring material shear yield strength, k =226.32MPa, b is the ring height, b =105mm, L is the contact arc length, L =1.74mm, h₀Is radial wall thickness, h₀=90mm, m is the friction factor, m = 0.7;

further, the actual forming deformation is the rolling ratio lambda of the sectional area of the intermediate blank of the ring blank after the open die forging local deformation to the sectional area of the final ring piece. In this embodiment, the sectional area of the intermediate blank of the ring blank after the local die forging deformation is 9358mm²The sectional area of the final ring piece is 5267 mm²And λ is 1.77.

The invention relates to a local die forging and rolling combined forming method of a titanium alloy, which adopts the technical scheme of saw cutting, heating, upsetting, punching, die forging and ring rolling.

Compared with the prior art, the invention has the following advantages: large allowance machining is not needed, no trimming step is needed, the material utilization rate is improved to the maximum extent, and the integrity of a forging flow line is reserved; multiple ring rolling is not needed, and the special-shaped prefabricated ring blank prepared by local die forging can be completely filled in a ring rolling die; the process is simple, complex forging impression and large-tonnage complex forming equipment are not needed, the cost of the forge piece is saved, and the technology is suitable for various enterprises.

Therefore, the local die forging and rolling combined forming method for the titanium alloy T-shaped section ring piece can effectively simplify the process flow, and the titanium alloy ring piece with excellent mechanical property can be manufactured by using a low-cost process method and low-cost equipment.

The foregoing examples and description merely illustrate the principles of the present invention and are not intended to limit the scope of the method. For the special-shaped ring forgings with different shapes, special-shaped ring pieces with different cross-sectional shapes can be prepared only by changing the shape of a die cavity of a local die forging and the shape of a ring rolling die. Various non-inventive changes and modifications related to the present invention are within the scope of the present invention.